This story has been updated with information about a GoFundMe account.

For seven years of marriage, Libby Davis was a "rock" for her husband, Kevin. He said she was "a bright light in this world."

But there was also darkness. The 28-year-old mother suffered from postpartum depression and, on Wednesday, drove off the Bush Turnpike in Plano, crashing into a grove of trees near Preston Road and leaving her car behind.

In a heartfelt Facebook post, Kevin Davis paid homage to his wife, a special-education teacher and mother to their daughter, 20-month-old Michelle. Their baby, who called her mother "mama," was not in the car.

"It's with an extremely heavy and broken heart to say my beautiful wife of 7.5 years, my rock, and Michelle's 'mama' has passed away from this life. Libby was such a bright light in this world, but if you knew her, then of course my telling you is completely superfluous," Kevin Davis wrote on Facebook.

Davis declined to talk further Friday, saying on Facebook that fitting words were hard to find.

"Words can't express the loss this is for me and our baby; that Michelle will grow up without her sweet loving mother is a fact that I can hardly stomach. ... I feel so lucky to have been married to this stunning angel of a human being for the time I had."

He posted eight pictures of happier times: Libby Davis and Michelle smiling in the snow; a selfie that Libby took in the driver's seat of a car; a family photo taken not long after Michelle was born.

A GoFundMe account was created to support Michelle and her father and to pay for funeral expenses. Libby Davis did not have life insurance because of a pre-existing medical condition, the page says.

Libby Davis was a teacher at Hendrick Middle School in Plano. Her Facebook bio describes her as "Libby = Friend. Daughter. Sister. Special Needs Teacher. Wife. Momma. Missionary Kid. Texan."

According to Facebook, she "grew up drinking coconuts and swimming in ocean as a missionary kid in the Solomon Islands. She attended high school in the highlands of Papua New Guinea."

In a Facebook post from June of last year, Libby Davis wrote parents should "just love the snot out of your kids and be there for them."

There are no more recent posts on what is now a memorial page.

On Friday, Kevin Davis closed his own post with a message for his wife and his daughter.

"Michelle, we got this love — me you against the world!" he wrote. "Libby — I'm gonna miss you more than you'll ever know."

Postpartum vs. "baby blues"

Postpartum depression is more intense and lasts longer than "baby blues," a term used to describe the worry, sadness and tiredness many women experience after having a baby, according to the Centers for Disease Control and Prevention.